Melt spinning method of polyamide yarn

ABSTRACT

This invention involves the melt spinning of polyamide yarn containing 0.001 to 0.05% by weight of the polyamide of one or more compounds from the following group: magnesium acetate, magnesium chloride, magnesium bromide, magnesium nitride; and 0.05% to 5% by weight of one or more compounds from the following group: dithiocarbamate metallic salts, thioethers of fatty acids, 2-mercaptobenzimidazol, 2-mercaptobenzimidazol metallic salts, and 2,2&#39;&#39;dibenzimidazol disulfide. The added compounds reduce the accumulation of carbonized material at the spinneret orifice.

United States Patent 11 1 Goto et a1.

1 51 Sept. 23, 1975 MELT SPINNING METHOD or POLYAMIDE YARN [75]lnventorsz Michio Goto; Shogo Ito; Atuio Tanaka, all of Mihara, Japan[52] US. Cl. 260/45.75 C; 260/457 R; 260/4575 W; 260/4585 S; 260/458;260/45.9 R [51] Int. C1. C08G 85/00 [58] Field of Search 260/4575,45.85, 45.8, 260/459 [56] References Cited UNITED STATES PATENTS2,705,227 3/1955 Stamatoff 260/457 FOREIGN PATENTS OR APPLlCATIONS650,173 1/1965 Belgium 260/4575 842,271 7/1960 United Kingdom 260/4575969,154 12/1950 France 260/459 1,159,299 6/1958 France 260/4575 PrimaryExami/1erV. P. Hoke Attorney, Agent, or FirmRichard A. Anderson [57]ABSTRACT This invention involves the melt spinning of polyamide yarncontaining 0.001 to 0.05% by weight of the polyamide of one or morecompounds from the following group: magnesium acetate, magnesiumchloride, mag nesium bromide, magnesium nitride; and 0.05% to 5% byweight of one or more compounds from the follow ing group:dithiocarbamate metallic salts, thioethers of fatty acids,Z-mercaptobenzimidazol, 2- mercaptobenzimidazol metallic salts, and2,2'dibenzimidazol disulfide. The added compounds reduce theaccumulation of carbonized material at the spinneret orifice.

4 Claims, N0 Drawings 1 MELT sPINNINo METIIoD or POLYAMIDE YARNBACKGROUND OF TI-IE INVENTION This invention is concerned with the meltspinning method of polyamide. Especially, this invention is the methodfor preventing a single filament break produced by accumulation ofcarbonized volatile materials such as 'monomergand oligomer on thespinneret surface during the melt spinning of polyamide.

. During. the-prolonged melt spinning ofpolyamide, volatile materials,such as monomer and oligomer adhere to the spinneret surface; after atime they are oxiclized in high temperature surroundings and accumulateas carbonized material. This carbonized material accumulated on thespinneret surface produces a bend ing phenomena of the molten stream ofpolyamide during spinning. The end result produces drips or singlefilament breaks caused by the enlarging, bending and adherence of themelted polyamide on the spinneret.

For this reason, spinning must be regularly stopped for cleaning of thespinneret surface which reduces productivity.

Presently, there are various methods existing for elimination of thesedefects. For example, there are methods concerned with spinningequipment, such as sealing of the surface below the spinneret withnonreactive gas, changing spinneret capillary shapes, or applyingsilicone oil on the spinneret surface. But these methods were not givingthe desired effect for the prevention of single filament breaks.

SUMMARY OF THE INVENTION This invention is the mixing of a magnesiumsalt and a sulfur containing organic ionic compound into the polyamideto reducethe accumulation or carbonized materials on the surface of thespinneret being there fore effective in preventionbf a single -filamentbreak.

In other words, this invention" is' the melt spinning method ofpolyamide characterized by the meltspinning of yarn with polyamidecontaining 0.00l to 0.05% by weight of the polyamide'of a compoundselected from one or moreof the following: magnesium acetate, magnesiumchloride, magnesium bromide, magnesium nitride; and 0.05 to 5% by weightof a compound selected from one type or more of the following group:dithiocarbamate metallic salts, thioethers of fatty esters,2-mercaptobenz'imidazol, 2- mercaptobenzimidazol metallic salts, and2,2- dibenzimidazol disultide. I

DESCRIPTION or PREFERRED EMBODIMENTS This invention is concerned with asuperior effectiveness in preventing a single filament break during themelt spinning of polyamide by using especially magnesium salt and sulfurcontaining ionic organic compounds as previously described. The othermagnesium salts, for example, combination of magnesium oxide,

magnesium sulfide, etc. with the abovedescribed sulfur containing ionicorganic compounds will not give effectiveness in preventing a singlefilament break.

Independently applying the magnesium salts or sulfur containing ionicorganic compounds used in this invention will not give fulleffectiveness.

A remarkable effectiveness is obtained in prevention of single filamentbreaks when applying the combination of both compounds of thisinvention.

In this invention method, the magnesium salt addition is 0.001 to 0.05%by weight to polyamide. In case of using less than 0.001% byweightresults in easy oc currence of a single filament break during thespinning. The use of higher than 0.05% by' weight will reducepolymerization rate when added during the polymerization, or lower theviscosity when impregnated onto chips during the spinning.

The dithiocarbamate salts used in this invention method are, forexample, the sodium, zinc, copper, selenium, thallium salts ofdithiocarbamate, such as dimethyl dithiocarbamate, diethyldithiocarbamate, di-nbutyl dithiocarbamate, ethyl phenoldithiocarbamate.

The 2-mercaptobenzimidazol metallic salts are, the zinc, copper andmagnesium salts of 2- mercaptobenzimidazol. And, for example, thethioethers of fatty esters are dilauryl 3,3'-thiodipropionate, distearyl3,3'-thiodipropionate, etc. The amount of addition of these organiccompounds is 0.05 to 5% by weight to polyamide. Use of less than 0.05%by weight resultsin insufficient effectiveness in prevention of singlefilament breaks. Use of more than 5% by weight affects physicalproperties of yarn, i.e. strength is lowered, therefore, such largeamounts are not favorable.

In this method, previously described magnesium salts and organiccompounds can be incorporated into the raw material of polyamide beforepolymerization, or added during polymerization, or mixed with polyamidechips. It follows that these additive containing polyamides will be meltspun, but the melt spinning method is not critical. Either a melter typeor extruder type can be used. The extruder type is preferred because itwill result in uniform yarn quality.

The polyamides used in this invention can be, for example, the polyamidefrom w-lactam such as poly-e c'aprolactam, poly-w-nonamide,poly-m-lauryl lactam, also the polyamides obtained from diamines andcheerboxylic acids and their copolymers or blends of various polymers ofpolyhexamethyleneadipamide, polyhexamethylenesebacamide,polyhexamethylene isophthalamide, when these polymers can contain aluster agent, heat stabilizer, ultra violet light stabilizer, antistaticelectricity agent, terminator, and optical brightner.

Based on this invention that the bending phenomena of melted polyamideon the spinneret surface is greatly reduced, furthermore remarkableextension of time for a single filament break occurs which results in aremarkable'extension of time for spinneret surface cleaning cycle.

EXAMPLES The actual examples are as follows. ln the inherent viscositygiven in the examples were calculated from the viscosity measurement inmeta-cresol at 30C., and the parts given in examples are all on theweight basis.

ACTUAL EXAMPLES 1-5, COMPARISON EXAMPLE l-6 After polymerizing parts ofthe e-caprolactam, and 1 part water for four (4) hours in the autoclaveat 265C, various magnesium salts and sulfur containing organic ioniccompound were added, then nitrogen blanket pressure was graduallyreduced.

Chips of poly-e-caprolactam (inherent viscosity 1.42) using 40 grams perdenier ratio extruder chips were spun with the following conditions:280C. spinning temperature, 600 m/minute spinning speeds, 28C. coolingair temperature and using a spinneret having 0.6 l/d ratio capillaries.The measurement of occurrence time for the bending or a single filamentdithiocarbamate metallic salts, thiodialkanoic acid esters,Z-mercaptobenzimidazol, Z-mercaptobenzimidazol metal salts,

break was made on the first occurrence time with using d a prev1ouslysilicone oil sprayed spinneret during spinzgtdib i i d i lfl nmg. Theaverage values of measurements are shown in Table I. For comparison,poly-e-caproamide is ob- The method of clalm 1 wherein the p y d tained(inherent viscosity, 1.45) without using above P y P described magnesiumsalts or sulfur containing organic A method to reduce bullddlp ofcarbonized mateionic compounds. The first occurrence time of the on theSurface ofaspmneret during Spinning of y bending or a single filamentbreak was measured. The thetic lineal Poll/amides having ecurring amidegroups average values of measurement are shown in Table l. conslstmg 0fTABLE 1 Occurrence Occurrence Time of Actual Magnesium lon ContainedTime of Single Filament Example Salt (Part) Organic Compound (Part)Bending (Hour) Break (Hour) 1 Magnesium Acetate 0.05 Zinc diethyldithiocarbamate 0.5 32 55 2 Magnesium Nitride 0.03Z-mercaptobenzimidazol 0.3 33 58 3 Magnesium Chloride 0.05Diluuryl-3,3-thimlipropionate 0.5 37 63 4 Magnesium Bromide 0.01 copperZ-mercaptohenzimid:ilol 0.4 29 56 5 Magnesium Bromide 0.012,2'-diben7.imidazol disulfide 0.2 28 55 Comparison Example 1 None None7 l3 2 Magnesium Nitride 0.03 None 14 23 3 Magnesium Chloride 0.05 None28 4 None 2.mcrcaptobenzimidazol .3 16 30 5 None Dilauryl3,3'-thiodipropionate 0.5 15 29 6 Magnesium Oxide 0.05 Zinc diethyldithiocarbamate 0.5 15 27 From Table 1, it is shown the remarkableextension of a single filament break occurrence time. Again it is shownthat use of other magnesium salt as used in this invention, such asmagnesium oxide with sulfur containing ionic organic compound will notgive the supe-' rior effectiveness as the result obtained from thisinvention.

We claim: 1. A method to reduce build-up of carbonized material on thesurface of a spinneret during spinning of synthetic linear polyamideshaving recurring amide groups consisting of spinning a polyamidecomposition comprising a polyamide containing from about 0.001 to about0.05% by weight of the polyamide of a compound selected from the groupconsisting of magnesium acetate, magnesium chloride, magnesium bromide,and magnesium nitride, and

from about 0.05 to about 5% by weight of the polyamide of a compoundselected from the group consisting of spinning a polyamide compositioncomprising a polyamide containing from about 0.001 to about 0.05% byweight of the polyamide of a compound selected from the group consistingof magnesium acetate, magnesium chloride, magnesium bromide, andmagnesium nitride, and

from about 0.05 to about 5% by weight of the polyamide of a compoundselected from the group consisting of the sodium, zinc, copper, seleniumand thallium salts of dithiocarbamate, dilauryl 3,3'-thiodipropionate,distearyl 3,3 '-thiodipropionate, Z-mercaptobenlzimidazol, zinc, copperand magnesium salts of 2-mercaptobenzimidazol, and 2,2-dibenzimidazoldisulfide.

4. The method of claim 3 wherein the polyamide is polycaprolactam.

1. A METHOD TO REDUCE BUILD-UP CARBONIZED MATERIAL ON THE SURFACE OF ASPINNERET DURING SPINNING OF SYNTHETIC LINEAR POLYAMIDES HAVINGRECURRING AMIDE GROUPS CONSISTING OF SPINNING A POLYAMIDE COMPOSITIONCOMPRISING A POLYAMIDE CONTAINING FROM ABOUT 0.001 TO ABOUT 0.05% BYWEIGHT OF THE POLYAMIDE OF A COMPOUND SELECTED FROM THE GROUP CONSISTINGOF MAGNESIUM ACETATE, MAGNESIUM CHLORIDE, MAGNESIUM BROMIDE, ANDMAGNESIUM NITRIDE, AND FROM ABOUT 0.05 TO ABOUT 5% BY WEIGHT OF THEPOLYAMIDE OF A COMPOUND SELECTED FROM THE GROUP CONSISTING OFDITHIOCARBAMATE METALLIC SALTS, THIODALKANOIC ACID ESTERS,2-MERCAPTOBENZIMIDAZOL, 2-MERCAPTOBENZIMIDAZOL METAL SALTS, AND2,2''-DIBENZIMADAZOL DISULFIDE.
 2. The method of claim 1 wherein thepolyamide is polycaprolactam.
 3. A method to reduce build-up ofcarbonized material on the surface of a spinneret during spinning ofsynthetic linear polyamides having recurring amide groups consisting ofspinning a polyamide composition comprising a polyamide containing fromabout 0.001 to about 0.05% by weight of the polyamide of a compoundselected from the group consisting of magnesium acetate, magnesiumchloride, magnesium bromide, and magnesium nitride, and from about 0.05to about 5% by weight of the polyamide of a compound selected from thegroup consisting of the sodium, zinc, copper, selenium and thalliumsalts of dithiocarbamate, dilauryl 3,3''-thiodipropionate, distearyl3,3''-thiodipropionate, 2-mercaptobenzimidazol, zinc, copper andmagnesium salts of 2-mercaptobenzimidazol, and 2,2''-dibenzimidazoldisulfide.
 4. The method of claim 3 wherein the polyamide ispolycaprolactam.